Which document must be appointed in writing for the SSO and subordinate SSOs?

The correct answer is the Security Clearance Record, as this document plays a crucial role in establishing the security clearance status of individuals appointed to sensitive positions, including the Security Security Officer (SSO) and subordinate SSOs. The Security Clearance Record provides verifiable information about the individual's eligibility to access classified information based on background checks and assessments.

In a security context, having a clear and documented security clearance status ensures that individuals entrusted with sensitive responsibilities meet the required standards for safeguarding national security. The appointment of SSOs and subordinate SSOs in writing is integral for accountability and formal recognition of their roles, and the Security Clearance Record helps to confirm that the appointed personnel have undergone the necessary vetting.

Other options, such as the Personnel Security Agreement, Security Support Statement, and SOP for Security Officers, play roles in various aspects of security management but do not specifically establish the formal appointment of personnel in the same way that the Security Clearance Record does.